Abstract Preserving the health of patients living with HIV and achieving an end to the HIV epidemic depend upon expanding ART access and assuring treatment success. In Haiti, the country most heavily impacted by HIV/AIDS in the Caribbean region, use of ART has scaled up dramatically; however, concerning levels of attrition, sub-optimal adherence, and suspected treatment failure have been observed. Building upon preliminary research establishing the validity of an electronic medical record (EMR)?based alert, the proposed research project will develop and pilot test a provider-based intervention using an electronic alert together with brief ART adherence counseling to improve ART adherence and reduce the incidence of ART treatment failure. This innovative intervention leverages the existing nation-wide iSant EMR system and offers potential for wide-scale impact on care delivery and patient adherence, by targeting scarce personnel and resources toward those most in need. The aims of the project are to: 1) conduct formative research on the potential role of EMR alerts and healthcare providers in ART adherence counseling in Haitian HIV primary care clinics; and 2) conduct a preliminary clinical trial of the iSant Plus intervention. The research study involving mixed methods will take place in two large public-sector ART clinics in Port-au-Prince, where the multidisciplinary MPI research team has establish relations during a decade of prior collaborations. A formative evaluation phase using mixed methods will examine provider and patient beliefs and attitudes toward the EMR-based alert and provider-based ART adherence counseling. This work will inform the design and development of the iSant Plus intervention. A pilot study of the feasibility and acceptability of the intervention using a quasi-experimental study design will be carried out in one intervention and one control ART clinic. Outcomes of interest include retention in care, ART adherence, incidence of ART treatment failure by WHO immunologic and clinical criteria (all measured using routine EMR data), and HIV viral suppression (measured using HIV-1 viral load testing in a sub-sample of patients). Patient information, motivation, and behavior will be examined as mediating factors. Approximately 130 Haitian, Creole-speaking patients over age 18 who have recently initiated a first-line ART regimen are expected to be enrolled in the study and to be followed for 9 months. While the study design and sample size will not be powered to measure effectiveness of the intervention, the trial will establish feasibility, acceptability, and study procedures relevant for a larger-scale trial using a cluster randomized or stepped-wedge study design at a national level in Haiti.